Views: 0 Author: Site Editor Publish Time: 2024-08-27 Origin: Site
Molecular sieve and activated alumina are commonly used adsorbents in industry, and both play an important role in industrial production. Both are dry adsorbents, then what is the difference between this activated alumina and molecular sieve? What is their role, only from the two structure, adsorption performance, application scenarios are different, in order to make a reasonable choice of products in industrial production.
1. The different structure between activated alumina and molecular sieve.
Activated alumina and molecular sieve is a porous highly dispersed solid material, have a large specific surface area, but from the distribution of structural holes can be seen on the difference between activated alumina and molecular sieve.
Activated alumina molecular formula: Al2O3-x(OH)2x. Activated alumina pore structure distribution is relatively messy, generally according to the pore size distribution score: microporous, medium pore, large pore. Activated alumina pore distribution is not very uniform.
Molecular sieve molecular formula: (M)2/nO-Al2O3-xSiO2-pH2O. molecular sieve in the structure of a number of pore channels with uniform pore size and neatly arranged pore holes. According to the different molecular ratios of SiO2 and Al2O3, molecular sieves with different pore sizes are obtained. Its models: 3A molecular sieve, 4A molecular sieve, 5A molecular sieve, 13X molecular sieve and so on.
2. The different applications between activated alumina and molecular sieve.
Activated alumina can actually be called industrial desiccant. More than 80% of the air pressure drying equipment commonly used in the industry are basically activated alumina, the normal can reach -40 ℃, only in the case of higher drying depth to the molecular sieve, can be used with activated alumina desiccant gas are: acetylene, cracked gas, coke oven gas, hydrogen, oxygen, air, ethane, hydrogen chloride, propane, ammonia, ethylene, hydrogen sulfide, propylene, argon, methane, Sulfur dioxide, carbon dioxide, natural gas, helium, nitrogen, chlorine and so on.
Molecular sieve has strong hydrophilicity, because in industrial production, sometimes the water content of the gas is required to be controlled at a very low level, the depth of activated alumina drying can not meet the requirements, molecular sieve can be adsorbed at a very low level of water content, molecular sieve drying depth of -70 ℃. At this time there is a problem, molecular sieve desiccant depth is so high, why we do not directly use the molecular sieve, molecular sieve cost is higher, sometimes not so high requirements words with molecular sieve will cause unnecessary waste. The difference between the two adsorption conditions, activated alumina in the case of gas moisture content is higher than the molecular sieve water absorption rate is much higher than the molecular sieve under the same conditions of molecular sieve is not activated alumina results are obvious, this is caused by the structure of the molecule, but in the level of moisture content is very low need to reduce the level of an order of magnitude, then the molecular sieve of the water absorption rate than the activated alumina to be strong. In fact, sometimes we can use activated alumina and molecular sieve together, so that we can play their respective strengths, both cost savings and can achieve twice the result with half the effort.
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